The meaning of JDK
● JDK is a software development toolkit of Java language, mainly used for java applications on mobile devices and embedded devices. JDK is the core of the entire Java development. It includes the JAVA runtime environment (JVM+Java system class library) and JAVA tools.
● JDK includes compilation tools and packaging tools. (Compilation tool → javac.exe) (Packaging tool → jar.exe)
JRE meaning
● Java Runtime Environment (JRE for short).
● There is a Java Virtual Machine (JVM) inside JRE and some standard class libraries (Class Library).
● If you only need to run a Java program or Applet, download and install it. If you want to develop Java software by yourself, please download JDK (the difference between JRE and JDK). JRE is included with the JDK.
The meaning of JVM
●JVM is the abbreviation of Java Virtual Machine. JVM is a specification for computing devices. It is a fictitious computer that is implemented by simulating various computer functions on an actual computer.
● After the introduction of the Java language virtual machine, the Java language does not need to be recompiled when running on different platforms. The Java language uses the Java virtual machine to shield information related to specific platforms, so that the Java language compiler only needs to generate the target code (bytecode) that runs on the Java virtual machine, and it can run on multiple platforms without modification. .
The correlation between JDK, JRE and JVM
Install JDK, JRE, JVM
Address: https://www.oracle.com/java/technologies/downloads/#java8
JDK installation details
Set environment variables
